HIGH-FREQUENCY ANTENNA ARRANGE FOR USE WITH A HIGH-FREQUENCY PCB

Abstract

High-frequency antenna arrangement (25), RF antenna arrangement (25) for use with an RF printed circuit board (24), RF PCB (24), with a PCB ground plane (27), wherein the RF antenna arrangement (25) has a longitudinal axis (11) and comprises the following: an intermediate arrangement (30), comprising: a substrate (31) that is spaced apart from the HF-PCB (24) and has an upper main surface (21) and a lower main surface (121); an intermediate mass layer (32) applied to the lower main surface (121) of the substrate (31) and defining one or more apertures (28) along the longitudinal axis (11); a dielectric layer (34) applied to the intermediate mass layer (32); and a linear microstrip track (38) configured as an antenna feed line and arranged on the dielectric layer (34), wherein the linear microstrip track (38) is configured to guide incident RF energy with a predetermined frequency range along the longitudinal axis (11); a plurality of conductive columns (36) which electrically connect the PCB mass layer (27) to the intermediate mass layer (32) and structurally support the substrate (31), so that the RF energy propagating along the linear microstrip track (38) is coupled via one or more apertures (28) to the upper main surface (21) of the intermediate arrangement (30); and a load element (50) which is connected in series with the linear microstrip track (38) at one terminal end of the RF antenna arrangement (25).

Description

Introduction

[0001] Automated driver assistance systems are used on board various types of vehicles to create comprehensive awareness of objects located near or in the vehicle's path. Such systems rely on a combination of complementary remote sensing technologies. Core technologies used in both human-driven and emerging autonomous vehicles may include radar or lidar systems, optical cameras, and vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication devices. Radar systems, in particular, are based on the propagation and reflection of electromagnetic waves to perform real-time object detection.The development of high-frequency (RF) transmission and signal processing technologies has driven corresponding advances in on-board radar systems, which are used in emerging systems such as adaptive cruise control, automatic brake assist, obstacle detection, high beam control, and automatic lane change / lane keeping.

[0002] In a typical radar system, a waveform embodying pulsed or continuous RF energy is generated and transmitted in a predetermined scanning direction, such as forward, transverse, and / or backward relative to a vehicle body. When the transmitted waveform encounters a sufficiently reflective object within its bandwidth and propagation range, a portion of the originally transmitted RF energy is reflected back to the RF transmitter as a return signature. The reflected energy is received by an antenna or transceiver, and the corresponding return signature is processed using onboard hardware and software for signal processing. In this way, a radar system is able to quickly determine a direction (i.e.,to determine the azimuth and elevation) and the corresponding area to detected objects near or in the vehicle's path, and finally to enable the control of actuators and / or the alerting of an operator who responds to the detection of such objects.

[0003] US Patent 5,694,134 A describes a phased-array antenna for microwave and millimeter-wave applications that uses either microstrip lines, coplanar waveguides, or other construction techniques employing a fixed dielectric transmission line. A continuously variable phase delay structure, used to control the radiation pattern of the phased-array antenna, can be applied in the construction of resonant frequency-tunable coplanar waveguide antennas and impedance-tunable quarter-wave transformers. A thin layer of barium strontium titanate (BaxSr1-xTiO3) or another nonlinear material such as PbZrxTi1-xO3 (PZT), LiNbO3, etc., is deposited onto the coplanar waveguide and / or the patch antenna element. The dielectric constant of the thin layer can be varied considerably by applying a DC voltage to the thin layer.The propagation constant of a transmission line is directly proportional to the square root of the effective dielectric constant (assuming a lossless dielectric). In an arrangement of several antenna elements provided with the feed structure using the disclosed transmission lines, the direction of the resulting main beam of the arrangement can be varied over a complete hemisphere by applying only two adjustable DC voltages to the dielectric thin films.

[0004] US 2017 / 0117638A1 describes an array antenna in which a plurality of radiating elements are arranged. The array antenna comprises: a first layer, which includes a first substrate forming the upper section of the array antenna, and several radiating elements arranged on the first substrate; a second layer, which includes a second substrate forming the lower section of the array antenna, and a feed line arranged on the second substrate to supply output power to the multiple radiating elements; and a third layer, formed between the first and second layers, comprising a base plate and an opening slot formed through the base plate. Description of the invention

[0005] The invention is defined by the claims.

[0006] An improved radio frequency (RF) antenna arrangement is disclosed herein for use with an RF printed circuit board (RF PCB). Such an RF PCB can be used as part of a radar arrangement to support an automated driver assistance system of the types generally mentioned above, where the term "driver" refers to human and / or autonomous computer-assisted / robotic operators of a vehicle. Furthermore, the term "support / assistance" can encompass various levels of torque, braking, steering, and / or speed support in controlling the current operating state or state vector of the vehicle, as well as the activation of audible, visual, and / or tactile warnings to the driver, with or without accompanying vehicle actuator control.

[0007] The RF PCB, which can be used with the disclosed RF antenna arrangement, includes a main surface on which a conductive ground plane layer is applied. This particular layer, which for clarity is also referred to herein as the "PCB ground plane," is at least one functional component of the disclosed antenna arrangement. In certain embodiments, the PCB ground plane can also be a structural component of the disclosed antenna arrangement.

[0008] The RF antenna array can optionally be configured to operate at subterahertz frequencies, such as in the range of approximately 228 GHz to 240 GHz in a particular embodiment. The antenna array is composed of one or more antenna elements, each having a corresponding aperture through an intermediate ground plane. Like the antenna array itself, the various apertures can be rectangular (in plan view), although oval, circular, or other shapes are used in other embodiments. The antenna element(s) terminate together in a load element, which can in turn be configured to dissipate and / or reflect the residual RF energy as described below.Incident RF energy that is directed into the antenna array, such as through a waveguide or other inlet to the antenna array, propagates along the longitudinal axis of the antenna array along a single linear microstrip track.

[0009] The axially propagating RF energy is progressively coupled to the corresponding aperture(s). When multiple apertures are used, they are spaced apart, for example, evenly spaced along the longitudinal axis. The energy coupled to the aperture(s) is radiated with precise relative amplitude and phase values. Such radiation can be amplified by using a suitable set of discrete patch antennas, as described herein. Excess RF energy remaining at the terminal end of the RF antenna array, i.e., at the outlet of a downstream or series last antenna element, is absorbed and / or reflected by the operation of the connected load element.

[0010] A multi-layered intermediate assembly forms an integral part of the disclosed RF antenna assembly. The intermediate assembly includes a substrate made of silicon, ceramic, quartz, organic materials, or another suitable material. The substrate has upper and lower principal surfaces, each corresponding to a top and a bottom of the assembly. The terms "top" and "bottom" refer to the normal orientation of the RF antenna assembly, which would normally be mounted on the vehicle, such that the plane of the substrate is perpendicular to the plane of a road surface on which the vehicle travels.Applied to the lower main surface of the substrate, in order of progression from the lower main surface, are: a ground plane layer (“intermediate ground layer”), which defines the aperture(s), a dielectric layer, and the aforementioned linear microstrip trace, the latter of which is the antenna lead-in. The substrate is spaced from the RF PCB by an intervening air gap and structurally supported by conductive pillars, e.g., solid cylindrical pillars made of copper or other conductive material. The pillars collectively couple the PCB ground plane to the intermediate ground layer and vice versa. The pillars have corresponding relative positions with respect to the aperture(s), which ultimately help to determine the frequency power of the antenna array, while simultaneously shielding the aperture(s) to prevent interference radiation from affecting the antenna performance.

[0011] The linear microstrip trace, which may take the form of an elongated copper element, wire, or other linear conductor, may slope toward or extend away from a common centerline of the apertures or longitudinal axis and optional patch antenna(s) along the longitudinal axis. As used herein, "common centerline" means that each aperture has a center point located along the longitudinal axis. For example, starting at the waveform inlet to the antenna array and continuing along the longitudinal axis, the microstrip trace may gradually slope or conically inward toward the common centerline or longitudinal axis.The degree of taper is configured to adjust the amount of RF coupling that occurs at various points along the longitudinal axis of the antenna array, for example, by increasing the coupling through tapering of the microstrip track toward the centerline as the RF energy propagates to the load element. Such tapering can be continuous or stepped. Other embodiments are conceivable in which the respective surfaces or sizes of the one or more apertures and / or the one or more patch antennas are varied along the longitudinal axis without changing the relative position of the microstrip track.

[0012] The RF antenna assembly, in its various embodiments, includes an intermediate assembly. This intermediate assembly comprises a substrate spaced apart from the RF PCB, having upper and lower main surfaces; an intermediate ground layer deposited on the lower main surface, defining multiple apertures spaced along the longitudinal axis; a dielectric layer deposited on the intermediate ground layer; and a linear microstrip track arranged on / within the dielectric layer. The microstrip track guides incident RF energy along the longitudinal axis within a predetermined frequency range, for example, approximately 228 GHz to 240 GHz in an exemplary sub-terahertz embodiment, where "approximately" means "within ±10 percent" or "within ±5 percent" in two possible embodiments.

[0013] The RF antenna array also includes a multitude of conductive pillars that electrically connect the PCB ground plane to the intermediate ground plane while structurally supporting the substrate. This allows the RF energy propagating along the linear microstrip track / longitudinal axis to be coupled towards and ultimately to the upper main surface of the intermediate plane through one or more apertures. A load element is connected in series with the linear microstrip track and is located at a distal / terminal end of the antenna array.

[0014] In some embodiments, the RF antenna arrangement is characterized by the absence of discrete patch antennas. Alternatively, such discrete patch antennas can be applied to or otherwise connected with the upper main surface of the substrate, with each of the respective discrete patch antennas being arranged opposite, i.e., over a base or surface of the corresponding aperture, the aperture being formed by the intermediate ground layer as described above.

[0015] In a non-restrictive example construction, the substrate of the intermediate arrangement is made of silicon, quartz, ceramic or an organic material, the patch antennas are made of copper foil, and the dielectric layer is made of bisbenzocyclobutene (BCB).

[0016] The load element can be implemented as a serial extension of the linear microstrip track. For example, a winding meandering line can include sinusoidal first and second segments of approximately equal length, with the segments arranged on opposite sides of the longitudinal axis. Alternatively, the load element can include a resistor connected in series with the microstrip track and coupled to an available electrical ground.

[0017] As mentioned above, the linear microstrip trace may taper or angle towards a common centerline of the apertures along the longitudinal axis of the RF antenna array. It is possible that the linear microstrip trace does not touch or intersect the longitudinal axis before terminating in the load element.

[0018] Some embodiments of the RF antenna arrangement include a plurality of (two or more) spaced-apart apertures, with six or more such apertures in some embodiments.

[0019] A monolithic integrated microwave circuit (MMIC) can be electrically connected to the linear microstrip track.

[0020] In another disclosed embodiment of the RF antenna arrangement, one or more antenna elements terminate together in the aforementioned load element. Each antenna element comprises a multilayer intermediate arrangement consisting of a substrate segment with upper and lower main surfaces defining an aperture, an intermediate ground layer segment defining the structure deposited on the lower main surface of the substrate segment, a dielectric layer segment deposited on the intermediate ground layer segment, and a linear microstrip track segment arranged on or within the dielectric layer segment.The conductive columns electrically connect the PCB ground plane and the segment of the intermediate ground plane and structurally support the segment of the substrate, so that the RF energy propagating along the linear microstrip track is coupled to the upper main surface of each of the different intermediate segments through the aperture(s) in each segment of the intermediate ground plane.

[0021] The above summary is not intended to represent every embodiment or aspect of the present disclosure. Rather, the foregoing summary merely illustrates some of the novel aspects and features presented herein. The features and advantages mentioned above, as well as other features and advantages of the present disclosure, will become apparent from the following detailed description of the embodiments and methods of carrying out the present disclosure in conjunction with the accompanying drawings and the attached claims. Brief description of the drawings Fig. Figure 1 is a schematic illustration of an exemplary radar system with a high-frequency (HF) antenna arrangement, constructed as shown herein. Fig. Figure 2 is an illustration of a schematic cross-sectional side view of a section or antenna segment of the RF antenna arrangement, shown in Fig. 1. Fig. Figure 3 is an illustration of a schematic perspective view of an RF antenna arrangement that can be used as part of the exemplary radar system of Fig. 1. Fig. Figure 3A is an illustration of a schematic top view of an optional embodiment of a load element that can be used with the RF antenna arrangement of Fig. 3. Fig. Figure 4 is an illustration of a schematic top view of the RF antenna arrangement, shown in Fig. 3 Fig. Figure 5 is a graph of the realized gain (vertical axis) versus the pattern angle (horizontal axis), with the power at 234 GHz of the exemplary RF antenna arrangement of Fig. 3 and Fig. 4 shown.

[0022] The present disclosure is open to various modifications and alternative forms, and some representative embodiments have been shown by way of example in the drawings and are described in detail herein. It is understood, however, that the inventive aspects of this disclosure are not limited to the specific disclosed forms. Accordingly, the disclosure is intended to cover all modifications, equivalents, combinations, sub-combinations, and alternatives that are within the spirit and scope of protection of this disclosure, as defined by the accompanying claims. Detailed description

[0023] Referring to the drawings in which the same reference numerals refer to the same components, a vehicle 10 is schematically illustrated in Fig. 1. The vehicle 10 includes a vehicle body 12 and, when configured as an exemplary motor vehicle as shown, a set of road wheels 14. Other vehicles can easily be considered, for example, rail vehicles, marine vessels, or aircraft, or the vehicle 10 can instead be implemented as a robot, mobile platform, or other system in which the present disclosure can be used to enjoy the aforementioned performance advantages. Therefore, the exemplary embodiment of the vehicle 10 is to be Fig. 1. The teachings presented here are to be illustrative and not restrictive, unless otherwise stated.

[0024] The vehicle 10 is equipped with a radar module (RM) 16, the radar module 16 comprising at least one high-frequency (HF) antenna array 25 configured as described in more detail below. A given vehicle 10 may include one HF antenna array 25 for an HF transmission function and another HF antenna array 25 for an HF reception function, or a single HF antenna array 25 may be used with a circulator (not shown), as the person skilled in the art will recognize. The radar module 16 utilizes properties of electromagnetic wave propagation and reflection at a predetermined discrete wavelength or frequency, or a predefined range thereof, to accurately detect the presence / range of objects located in the expected path of the vehicle 10.As such, the radar module 16 can optionally be arranged near a front end 12F of the vehicle body 12, such a position being advantageous when the radar module 16 is used to support forward and / or sideways driver assistance functions, such as, but not limited to, adaptive cruise control, automatic brake support, high beam control, lane change and lane keeping systems, etc.

[0025] Alternatively, the radar module 16 can be located elsewhere in relation to the vehicle body 12, such as at a rear end 12R, whereby the radar module 16 can be used for other useful purposes, including but not limited to emergency steering, parking and / or towing assistance functions.

[0026] The radar module 16 under consideration here includes a radar array 18 and a control unit (C) 20. When performing object and / or area detection functions, the radar array 18 can receive control input signals (arrow CC). I ) are transmitted to the control unit 20, whereby the control input signals (arrow CC) I ) indicate a detected position of / area to such detected objects. As part of the control input signals (arrow CC) I ) further information can be transmitted, including, for example, the size and identity of the detected obstacle.

[0027] In response to receiving the control input signals (arrow CC) IThe control unit 20 can send control output signals (arrows CCo) to a number of driver assistance systems 22, which are shown, for example, as representative driver assistance systems 22A, 22B, and 22C. Exemplary embodiments of the driver assistance systems 22A, 22B, and 22C can include one or more of the aforementioned adaptive cruise control, automatic brake support, obstacle detection, high beam control, parking assistance or backup assistance, and lane change / lane keeping systems. The control unit 20 can be an integral component or a separate module that is operatively connected to other resident control units of the vehicle 10 and is implemented as one or more digital computers, including a processor (P), e.g., a microprocessor or a central processing unit, and as memory (M) in the form of read-only memory, random access memory, electrically programmable read-only memory, etc.The control unit 20 can also include a high-speed clock generator, analog-to-digital and digital-to-analog switching logic, input / output switching logic and devices, and suitable signal conditioning and buffer switching logic.

[0028] Still referring to Fig. 1 The radar assembly 18 includes an RF printed circuit board (RF PCB) 24 on which the aforementioned RF antenna assembly 25 is mounted, the structure and function of the RF antenna assembly 25 being described below with regard to the Fig. 2-5 is described in more detail. The radar assembly 18 can include further components, such as radar integrated circuits (ICs) 26, each comprising one or more integrated, frequency-modulated, single-chip continuous-wave transceivers (FMCWs), which in turn are surface-mounted or mounted through the RF PCB 24. Such radar ICs 26 can be configured for operation in an example frequency band of approximately 76 GHz to 81 GHz in a non-limiting exemplary embodiment, e.g., within ± 5 percent or ± 10 percent.

[0029] As illustrated in the schematic side view in Fig. 2 shown, from the perspective of arrow A in Fig. 3. The RF PCB 24 includes or is connected to a first ground plane layer 27, hereinafter referred to as the “PCB ground plane” 27. The PCB ground plane 27 is applied to or otherwise connected to a first main surface 124 of the RF PCB 24. The RF antenna arrangement 25, which in a particular embodiment can be operated at approximately 228 GHz to 240 GHz, is constructed from a plurality of serially connected antenna elements 40 (see Figure 3). Fig. 3 and Fig. 4), wherein the construction of such an antenna element 40 in Fig. Figure 2 shows that some embodiments may use only the single antenna element 40, while others may use multiple antenna elements, e.g., six or more. The antenna elements 40 are configured similarly and thus form functional segments of the RF antenna arrangement 25, but with a subtle structural difference, as described below. Each antenna element 40 may optionally include a discrete patch antenna 26 arranged above a surface or base of an aperture 28 in the intermediate ground layer 32, the optional structure being shown in a phantom outline. The patch antennas 26 are constructed of suitable conductive material, such as copper foil, and may have a rectangular shape in plan view, as best illustrated in the following. Fig. 3 and Fig. 4 shown. For the patch antennas 26, circular, oval or other application-appropriate shapes can be used within the scope of protection of the disclosure, so that the special shape of Fig. 2 is exemplary and not limiting.

[0030] Integral to each RF antenna assembly 25 is a multilayer intermediate circuit board assembly, referred to below for simplicity as the intermediate assembly (INT-ASSY) 30. The intermediate assembly 30 includes a substrate 31 composed of silicon, ceramic, quartz, one or more organic materials, or another application-appropriate material. The substrate 31 has a top and bottom main surface 21 and 121, respectively, corresponding to a top and bottom surface of the antenna assembly 25. The substrate 31 is structurally supported with respect to the RF PCB 24 by a plurality of conductive pillars 36. In some embodiments, the substrate 31 can be fabricated with a thickness or depth (D1) of about 40–50 micrometers (µm).The maximum thickness depends on the materials used to produce the substrate 31, with the thickness or depth (D1) of substrates 31 made from organic materials being greater due to their lower dielectric constant, e.g., about 300 µm. Dimensions smaller than 40–50 µm are possible, down to a lower limit beyond which the production of the substrate 31 may no longer be feasible.

[0031] A second ground plane layer, hereinafter also referred to as the aforementioned intermediate ground plane layer 32, is deposited on the lower main surface 121 of the substrate 31. A dielectric layer 34, such as, but not limited to, bisbenzocyclobutene (BCB), is deposited on the intermediate ground plane layer 32, followed by the conductive linear microstrip track 38. In one possible embodiment, the dielectric layer 34 may be approximately 10–15 µm thick, with such a dimension for the dielectric layer 34 being represented as the corresponding thickness or depth (D2). Although in Fig. While the microstrip track 38 is depicted with a somewhat exaggerated thickness in Figure 2, it is significantly thinner, e.g., by 1 µm, and thus makes a negligible contribution to the overall thickness or depth (D3) of the intermediate arrangement 30. Therefore, the overall thickness or depth (D3), including the substrate 31, can be approximately 60–65 µm in one possible embodiment, without necessarily limiting the relative or absolute thicknesses to the values ​​shown.

[0032] The microstrip track 38 can be applied to or formed on the dielectric layer 34, with portions of the apertures 28 being etched into / through the intermediate ground layer 32. As explained below, the RF energy injected into the RF antenna assembly 25 and propagating along the length of the microstrip track 38 is coupled to one of the respective apertures 28, the apertures 28 being defined only by the surrounding structure of the intermediate ground layer 32. A single linear microstrip track 38 is thus injected into each subsequent antenna element 40 arranged in series. A total amount of the incident RF energy entering the RF antenna assembly 25 decreases progressively along a longitudinal axis 11 of the RF antenna assembly 25 by radiation and transmission along the microstrip track 38, as best described in the Fig. 3 and Fig. 4 shown.

[0033] Each of the aforementioned conductive columns 36 can be cylindrical and thus have a circular cross-section and a height (D4) of approximately 70–80 µm in an exemplary embodiment using the exemplary dimensions (D1, D2, and D3) listed above. In such an embodiment, the columns 36 can have a diameter (D5) of approximately 45–55 µm. In addition to providing structural support and spacing for the substrate 31 arrangement relative to the RF PCB 24, the various columns 36 extend between the intermediate ground layer 32 and the PCB ground layer 27, shortening them electrically and thereby preventing the propagation of RF energy between the PCB ground layer 27 and the intermediate ground layer 32. While the PCB ground plane 27 is an integral structural component of the RF PCB 24 in certain embodiments, the PCB ground plane 27 is considered an integral functional component of the RF antenna arrangement 25.Thus, the PCB ground layer 27 can be coupled to the conductive columns 36 before or after connection to the RF PCB 27.

[0034] Normally, the RF energy propagates along the linear microstrip track 38 and is incident on the apertures 28 in the intermediate ground layer 32, with the incident RF energy then radiating in both directions between a layer of the optional surface-mounted patch antennas 26 on the surface 21 and a layer of the microstrip track 38 between the intermediate ground layer 32 and the PCB ground layer 27. When a given aperture 28 is excited by the RF energy of the microstrip track 38, the aperture 28 tends to radiate in both the front (upward) and rear (downward) directions, as can be seen from the side view of Fig. 2. The term “parallel plate mode” refers to the energy radiated by the aperture 28 on the PCB side of the RF antenna arrangement 25, whereby this energy is trapped between the intermediate ground layer 32 and the PCB ground layer 27 and propagates outwards from the slot. The columns 36 prevent such a mode by short-circuiting the intermediate ground layer 32 and the PCB ground layer 27 together.

[0035] The conductive columns 36 of Fig. 2 are arranged with respect to the apertures 28, with one possible arrangement in Fig. 4 is shown. While in Fig. Figure 2 shows two columns 36. The actual number of columns 36 surrounding the various apertures 28, and the actual number of apertures 28, varies with the operating frequency of the RF antenna arrangement 25. For example, twelve such columns 36 can be used in each individual antenna element 40 in the embodiment shown in Figure 2. Fig. 3 and Fig. Figure 4 shows that the separation distance between a given column 36 and the aperture 28 of a corresponding antenna element 40 should be close enough to avoid exciting higher-order modes, i.e., less than half a wavelength or typically a quarter wavelength, far from the aperture 28. The separation of adjacent columns 36 is also important and should likewise be less than half a wavelength. Accordingly, the separation distances are highly design-specific. Thus, both the structure and the position of the columns 36 are tailored to achieve a desired frequency power of the entire RF antenna arrangement 25.

[0036] In some embodiments, the microstrip track 38 can be connected to a monolithic integrated microwave circuit (MMIC) 45. The MMIC 45 can be directly connected to the microstrip track 38, i.e., between the intermediate assembly 30 and the RF PCB 24, as shown, or the MMIC 45 can be mounted on the upper main surface 21 of the intermediate assembly 30 and connected to the microstrip track 38 using conductive through-contact surfaces (not shown). Regardless of the position of the MMIC 45, the MMIC 45 can be used to transmit 78 GHz transmit signals to the RF PCB 24 in certain configurations, with the RF PCB 24 then upconverting or frequency-multiplying the transmitted 78 GHz signals with signals of a desired frequency, e.g., 228 GHz to 240 GHz. The higher frequency signals are then sent or transmitted by the operation of the RF antenna arrangement 25.The MMIC 45 can downconvert the received 228 GHz-240 GHz signals into lower frequency signals, e.g., 77 GHz or 78 GHz, for further processing by the RF PCB 24. As a result, the example radar arrangement 18 can... Fig. 2 will be used to install a 228 GHz-240 GHz radar system for advantageous use on board the vehicle 10 of Fig. 1 or to manufacture in other applications.

[0037] The RF antenna arrangement 25 of the Fig. 1 and Fig. 2 is in Fig. Figure 3 schematically represents an extended arrangement of serially connected antenna elements 40, which terminate together in a load element 50. As stated above, in some configurations a single antenna element 40 can be used with the load element 50. Each antenna element 40 has the same components, which, although constructed as a unified whole, can be considered as "segments" that, as in Figure 3, are connected in a single configuration. Fig. 2 can be constructed. Thus, each antenna element 40 is defined by a segment of the intermediate arrangement 30 and therefore has a corresponding segment of the substrate 31, the intermediate ground layer 32, the dielectric layer 34, and the linear microstrip track 38, as well as some of the columns 36. Incident RF energy (arrow RF) IN The RF energy is guided into the RF antenna arrangement 25, e.g., by a waveguide 47 located at an inlet end 41 of the antenna arrangement 25. RF energy propagating along the length of the microstrip track 38 to the load element 50 is intermittently absorbed by the apertures 28 (see figure). Fig. 4) and coupled to the corresponding patch antennas 26, if such patch antennas 26 are used. The coupled energy is then radiated away from the apertures 28 / patch antennas 26 at a calibrated frequency / wavelength or band. In this way, most of the incident RF energy (arrow RF) is IN), which is directed into the antenna arrangement 25, e.g. 90 percent or more of the incident RF energy, is radiated away before it reaches the terminal or distal end 43 of the RF antenna arrangement 25, before it reaches the load element 50.

[0038] Excess RF energy remaining at the distal end 43 of the RF antenna assembly 25 can be partially reflected and dissipated by the operation of the load element 50, which is a serial extension of the microstrip track 38. That is, the load element 50 is specifically designed to reflect some RF energy with a certain reflection coefficient, which also includes a dissipative component. The meandering line 52 is thinner than / not as wide as the antenna feed line, i.e., the microstrip track 38, which contributes to generating the desired reflection coefficient. The value of the load reflection coefficient is determined as part of the design of the antenna assembly 25. It is also possible to design the RF antenna assembly 25 with a load that reflects all the energy back, but this typically reduces the operating bandwidth of the RF antenna assembly 25.

[0039] In one possible embodiment, the load element 50 can include a winding meandering conductor 52, e.g., a sinusoidal extension of the linear microstrip track 38 with a calibrated length suitable for dissipating the remaining RF energy. Thus, “sinusoidal,” as used herein, refers to multiple curves in alternating directions, and “wound” refers to an extended path of a particular pattern, including a random one.

[0040] For example, the load element can include a pair of sinusoidal dissipative segments 53A and 53B arranged on opposite sides of the longitudinal axis 11 and thus having approximately equal lengths. The total length of the meandering line 52 and / or each of the segments 53A and 53B is therefore significantly greater than the individual straight lengths of the segments of the linear microstrip track 38 within a given antenna element 40, e.g., 2 to 4 times longer. As the wave travels down the meandering line 52 in this embodiment, the power is dissipated, thus preventing the power from being reflected back to the antenna elements 40. Alternative configurations of the load element 50 that can function similarly include, as shown in Fig. 3A is shown as an alternative load element 50A, a resistor (R)-to-ground (GND) connection, where the resistor (R) is in series with the microstrip line 38 and connected to a conveniently located electrical ground. As noted above, the load element 50 could also be configured as a reflector to fulfill the desired functions.

[0041] With reference to Fig. 4. The RF antenna array 25 can be configured with subtle differences along its longitudinal axis 11 to provide a desired frequency power. Beam pattern sidelobes, examples of which are shown in Fig. The microstrip trace 38, as described below, can be controlled by arranging one axis of the microstrip trace 38 at a progressively changing distance (D6) with respect to the longitudinal axis 11 or centerline 51. A desired RF coupling is achieved by slightly moving the microstrip trace 38 away from the aperture centerline 51, with the microstrip trace 38 being located furthest from the centerline 51 in a first of the antenna elements 40 in the RF antenna arrangement 25, and gradually being moved closer to the centerline 51 in a last of the antenna elements 40 in the RF antenna arrangement 25, i.e., the antenna element 40 located immediately adjacent to the load element 50. The change in distance (D6) need not be linear along the axis 11.One effect of such a tapering level is stronger RF coupling and increased radiation through the respective apertures 28, as the RF energy propagates away from the inlet along the microstrip track 38. With the common centerline 51 of the various apertures 28, which is aligned coaxially with the longitudinal axis 11 of the RF antenna array 25, the amount of such tapering, which is in . Fig. 4 is not necessarily shown to scale, in an embodiment in which the taper along the longitudinal axis 11 is continuous, may be less than 5 degrees, or the taper may vary stepwise or discretely at each of the antenna elements 40.

[0042] Fig. Figure 5 shows an exemplary graph 60, which illustrates a possible antenna lobe pattern resulting from a simulation of the RF antenna arrangement 25. Fig.1-4. The realized gain in decibels (dB) is shown on the vertical axis with a beam angle (θ) in degrees on the horizontal axis, e.g., RF power at 234 GHz. If Z is the respective Cartesian axis arranged perpendicular to the plane of the patch antennas 26, and X is the axis of the microstrip track 38, then the angle (θ) lies in the XZ plane. An effective control of the sidelobes 64 is shown, i.e., about 20 dB below the nominal gain of the main lobe 62. The realized gain in this embodiment is about 8.5 dB, with a reflection loss of more than 10 dB.

[0043] Alternative configurations of the RF antenna arrangement 25 are possible, as a person skilled in the art would recognize from the aforementioned disclosure. As mentioned above, it is possible, for example, to remove the patch antennas 26 and allow the apertures 28 in the intermediate ground layer 32 to radiate directly. In such an embodiment, the RF antenna arrangement 25 and the individual antenna elements 40 are characterized by the absence of the patch antennas 26, so that the apertures 28 function as slot radiators 128. Such an approach has the potential advantage of simplifying the manufacturing process, eliminating the need for metal patterning on the upper main surface 21 of the intermediate arrangement 30. A potential disadvantage is that the bandwidth of the apertures 28 configured as slot radiators 128 may not be as large compared to configurations using the patch antennas 26.However, it may still be possible to achieve 128 application-appropriate bandwidths with such an optional slotted radiator configuration.

[0044] Other embodiments can enclose metallized contact holes through the intermediate arrangement 30 to isolate the antenna elements 40. While contact holes of this type can increase costs and manufacturing complexity, their use can reduce surface ripples that can be excited by the patch antennas 26. Such surface ripples can tend to decrease the radiation efficiency of the patch antennas 26 and produce ripples in the radiation patterns. The use of contact holes through the intermediate arrangement 30 also allows for the use of a thicker substrate 31, which in turn can reduce manufacturing costs.The foregoing description thus summarizes a usable structure that integrates commercially available radar ICs with front-end ICs and the present RF antenna arrangement 25 in a manner that enables cost-effective, high-volume manufacturing of a radar system 18 operating at frequencies above 100 GHz, e.g. 234 GHz.

Claims

[1] High-frequency antenna arrangement (25), RF antenna arrangement (25) for use with an RF printed circuit board (24), RF PCB (24), with a PCB ground plane (27), wherein the RF antenna arrangement (25) has a longitudinal axis (11) and comprises the following: an intermediate arrangement (30), comprising: a substrate (31) that is spaced apart from the HF-PCB (24) and has an upper main surface (21) and a lower main surface (121); an intermediate mass layer (32) applied to the lower main surface (121) of the substrate (31) and defining one or more apertures (28) along the longitudinal axis (11); a dielectric layer (34) applied to the intermediate mass layer (32); and a linear microstrip track (38) configured as an antenna feed line and arranged on the dielectric layer (34), wherein the linear microstrip track (38) is configured to guide incident RF energy with a predetermined frequency range along the longitudinal axis (11); a plurality of conductive columns (36) which electrically connect the PCB mass layer (27) to the intermediate mass layer (32) and structurally support the substrate (31), so that the RF energy propagating along the linear microstrip track (38) is coupled via one or more apertures (28) to the upper main surface (21) of the intermediate arrangement (30); and a load element (50) which is connected in series with the linear microstrip track (38) at one terminal end of the RF antenna arrangement (25). [2] RF antenna arrangement (25) according to claim 1, further comprising: at least one discrete patch antenna (26) connected to the upper main surface (21) of the substrate (31) and arranged over a corresponding one of the apertures (28). [3] RF antenna arrangement (25) according to claim 1, wherein the load element (50) is a coiled meander line (52) forming a serial extension of the linear microstrip track (38), and wherein the coiled meander line (52) is thinner than the linear microstrip track (38). [4] High-frequency antenna arrangement (25), RF antenna arrangement (25), for use with an RF printed circuit board (24), RF PCB (24) with a PCB ground plane (27), wherein the RF antenna arrangement (25) has a longitudinal axis (11) and comprises the following: a load element (50); one or more antenna elements (40) terminating together in the load element (50), each of the one or more antenna elements (40) having the following: a multilayer intermediate arrangement (30), comprising: a segment of a substrate (31) having an upper main surface (21) and a lower main surface (121) and defining an aperture (28); a segment of an intermediate mass layer (32) applied to the lower main surface (121) of the segment of the substrate (31); a segment of a dielectric layer (34) applied to the segment of the intermediate mass layer (32); a segment of a linear microstrip track (38) arranged on or within the segment of the dielectric layer (34) and configured to direct incident RF energy in a frequency range of at least about 228 GHz along the longitudinal axis (11) to the load element (50), wherein the segment of the linear microstrip track (38) is not parallel to the longitudinal axis (11) of the RF antenna arrangement (25); and a plurality of conductive columns (36) that electrically connect the PCB mass layer (27) to the segment of the intermediate mass layer (32) and structurally support the segment of the substrate (31), so that the RF energy propagating along the linear microstrip track (38) is coupled to the upper main surface (21) of the intermediate arrangement (30) through the aperture (28). [5] RF antenna arrangement (25) according to claim 4, wherein the RF antenna arrangement (25) is characterized by the absence of discrete patch antennas (26). [6] RF antenna arrangement (25) according to claim 4, wherein the RF antenna arrangement (25) includes a plurality of antenna elements (40) connected in series. [7] RF antenna arrangement (25) according to claim 4, wherein the multilayer intermediate arrangement (30) includes a discrete patch antenna (26) which is connected to the upper main surface (21) of the segment of the substrate (31) and is arranged above the aperture (28). [8] RF antenna arrangement (25) according to claim 4, wherein the load element (50) includes a coiled meander line (52) which forms a sinusoidal extension of the linear microstrip track (38). [9] RF antenna arrangement (25) according to claim 4, wherein the segment of the linear microstrip track (38) tapers or angles in the direction of the longitudinal axis (11). [10] RF antenna arrangement (25) according to claim 4, further comprising a monolithic integrated microwave circuit (45), MMIC (45) which is electrically connected to the linear microstrip track (38).

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